rohrmann



K. F. ROHRIVIANN.

ARTIFICIAL HAND. APPLICATION FILED OCT. 20. 1917- 1,305,169, Patented May 27,1919.

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K. F. ROHRIVIANN.

ARTIFICIAL HAND.

APPLICATION FILED OCT-20, 19x1.

LSQA 6 Patented May 27, 1919.

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'mz NORRIS PETERS co rwomumm wAsuuvnmnI a c KARL FELIX ROHRMANN, OF ST. GALLEN, OF SWITZERLAND.

ARTIFICIAL HAND.

Specification of Letters Patent.

Patented May 27, 1919.

Application filed October 20, 1917. Serial No. 197,720.

To all whom it may concern:

Be it known that I, KARL FELIX Ronn- MAN N, a citizen of the Swiss Confederation, and residing at St. Gallen, Switzerland, have invented certain new and useful Improvements in Artificial Hands, of which the following is a specification.

The present invention relates to an improved artificial hand in which the rotary movement of the forearm stump is used to actuate the thumb and the rest of the fingers; and the invention essentially has for its object to provide means for interdependently coupling the arm stump, the thumb and the four fingers in such manner that upon rotation of the stump in the one or the other direction the thumb and the fingers are simultaneously operated for closing or opening, as the case may be; the invention further enables the wearer of the prosthetic hand to rotate it with all its operative parts relative to the arm stump without actuating at the same time the thumb and the fingers, so that then objects clutched by the hand are held fast, no matter in which direction the stump or the hand are rotated; and lastly, the hand may be adjusted to various initial positions relative to the stump for the execution of diverse operations without the first stated capability of thumb and fingers to cooperate simultaneously being suspended, as in the second instance.

My invention will best be understood when described in connection with the accompanying drawing, in which Figure 1 represents a rear view of the prosthetic hand, with the cover removed to expose the interior, and partly in section; Fig. 2 shows a side elevation, partly sectioned, of the hand part proper; Fig. 3 represents a side elevation of one of the. fingers; Fig. 41 shows a section on line A-A'of Fig. 2, Fig. 5 a side elevation of Fig. 4. Fig. 6 illustrates a, further fragmental side view of the hand, the shell being sectioned to expose the internal parts; Figs. 7 and 8 are cross-sections on lines BB and CC respectively of Fig. 6, and Fig. 9 is a fragmentary side elevation, partly in section, of the coupling mechanism. The upper arm bars or straps 1 extend from the brachial sleeve 2 and are pivotally connectedat3' to the forearm straps 3. To

the latter is" fixed the wrist member 1 of. the

inverted dish shape, the straps 3 dish 4 forming the prosthetic substitute for the forearm. To the dish 4; are secured by means of rivets 5 the disks 6 and 7, of which the latter is provided with a hub or boss 8 within which is rotatably arranged the hub 10 of a larger hand-supporting disk 9, and the two hubs are secured against relative inadvertent displacement in longitudinal direction by the nut 11. The hub 10 freely rotates about the pivot pin 12 extending from the slightly vaulted. plate 13, from the lower face of which extends the screw bolt 13 A yoke member 14 is pressed against this plate 13 by a nut 15 threading on the bolt 13*, and a pin 1 1 extends from the yoke and is adapted to engage in one of the bores 13 in the plate 13, so that the yoke and the plate can be relatively adjusted in dif ferent initial positions. To the yoke member 14 is secured the forearm socket or cuff 16, adapted to be laced onto the arm stump and of varying length, depending upon the length of stump to be fitted. Above the pivot in 12 is provided with a square portion 1 and endsin a threaded end 18, and it is held near its upper extremity in the bracket support 19 fixed to the palm interior, as clearly shown in Fig. 1. To the square portion 17 of the pin 12 are fitted the toothed segment 20, the tubular spacing member 21, and the forked lever 22, the nut 23 holding the parts in position.

To the disk 9 is secured in suitable manner, for instance by screws, not shown in the drawing, the hand 25 having a removable cover 24: in the back thereof. v

A slightly arched spring lever 26 is secured atone end to the hand disk 9 by a screw stud 27: and a tooth 28 extending downwardly from the other down-curved end of this lever passes, through acorresponding aperture 9 in' disk 9 and selectively cooperates with a plurality of recesses 29in the wrist member 4 (Fig. 9). A hand operable coupling lever 31 is pivotally secured by a pin 30 with its one endto the hand disk 9 and is provided near thefree end extending beyond the base of the hand with a downwardly directed tooth 32, which is designed to cooperate with a rack segment33 on the disk 9 upon actuation of the coupling lever 31. A pressure spring 30 tends to normally force this lever into its inoperative position out of coaction with the rack. segment 33. A dog 34; is fulcrumed on a Eaters! extension as the j'ourrraleetend of tion of its ppert,. .ever- 1 pre uresp i g 36 tends to force the dog 34 into engagement with the toothed segment 20, whlch latter, as above stated, rotates in positive manner wlth the pivot .pin 12. The lower endof .the pinv 30 extends downwardly through disk 9 into I a guideway 57 provided in the superposed disks 7 and 4, for limiting the rotary displacementof the hand relative to the wrist.

With the fork 22 cooperates the lever 37, which widens into a plate and is secured within the hollow hand to the root 38 of the thumb 3 9, whichlatter can be turned about the pivot 40. pin ll 01 the upp'erextension 42' of-lever 37 cooperates with the forked end 4:3 o fthe lever l4: secured to the forefinger 43,,and the latter is rigidly con nected to thejniiddle {finger 4:5, both being fulcrurned qntheisl aftad. The-arm 4L7 laterally extending from the lever is pro vided with lugs 4L8 into which thread the link members 49. v.ll ro'these latter are se. cured the actuating nen bers 50 for the middle joints 5,1, 52 of the gold linger 53 and the little finger 54, and which members are preferably in the form of tightly coiled prin ei -te y e ure t hefin j te- The parts 51 and 52 are respectively pivoted at55 and 5.6 to the body ofthe hand, and the remaining finger joints 53 and 54 are sim rly jo nted t the midd j in and meit y a ated by sp in Which .eXr tend [freely through suitable bores in the th rwise soli ng r joints, as well known in the art; The fingers on'the r inner faces are preferably covered with Rubber or simila r material. 7

Afdraw spring 55 is secured with its one end to the inside of the hand and with its the en t a p n 56, xt n ing from the humb root 8 ga The sleeve 2 is strapped to the upper arm and the socket 16to the forearm stump. If, s shown n the dreii insth te th .28 or 1 1 21, ha repp dint eiieof the re e ses 2 in he'w i t member a n the' qe h is out i 'ef vensegenwr wi h h d the arm s amp is ew turned, the pivot pin 2 wil kew s in he ens and eethe m mbers 29; 2, and 23-e1 t p n- The. l v eeep retil g wit th fork of the lever 22, will also he. swung'abou its PiYot 40 with the resul th t the. thumb es well as the fingereeaee end else hefi 53,154: are a uated. Th fingers 4.3 5,

as ahe e described, are influenced by the ever x en'ei n 4: a1id1erer a; nd the fin: as 1 an a by the eetan lile ly ex end: ng arm a and th rd e pr n s If the stump is ro ated in'the seamen )ef th arnew 4! (F g- :l), t hand wi l. th n up; if

rot ted i ill nse elf a ms? 12; the hand wil ele e the thumb. asin i th fee bending overtoward the ballot the'thunib.

Into this position the fingers can also be v.niovedzby the action of the spring 55. Thus, by-rotating the arm stump in the one or the other direction the hand can be inade'to grasp objects andndrop them again, the

grasping pressure or hold being regulated by the force transmitted from the stump by the pivot pin 12. r r For different work manipulations different positions of the hand relative to the forearm are required. For thisl purpose the tooth 28 is lifted out of therespective recess 29 by operation of the 'locklever26 and the hand is then turned by the otherliand into the required relative position; this, however in'ayalso be ,done by rotating the stump to the required: extent. In the ,desired position, the tooth 28 is allowed 'to drop into t'he nearest recess 29, which rigidly couples the wrist and the hand, and the fingers can then aga b a t a d by t e mo n of th stump as abovedesciii'bed, V

For rotating tile hand after the fingers have closed about an ohject turning the tump, wi hent having he fingers let g again of theclutched object by inadvemently pe ing up, the upl n lever 31 i s ted y heed, ward h -r gh ve the reek s meet 33, hich-brings its depending tooth 32 into gagemen wi h th ratch t-te th h reef- Th s sh t nov ui n iofl ve :1- causes the following two operations to vtaliie place: The dog 34' is swung about the fu lcru n 30 towardthe toothed segment 20, fast On Piv Pi :1 endi fo ed y i s spr ng underneath in operative contact with the downicurvecl end of the lock lever ,26, so that the depending lever tooth 28'wi11 be lifted out of the recess 29 in the wrist memher 4, with the result that now the hand, with the fingers in flexed and lockedposition, is free to the{rotated by the stump in the one or the other direction, without possibilityvof the fingers inadvertently opening again. 7

For reestablishing normal operation, the coupling lever 31 is shifted back ofi the rack segment 33, which lets the lever tooth 28 down again for intercoupling the hand and the wristand which disconnects at thesam'e time the dog .34: fromthe ratchet segment 20, so that the stump will then actuate .onlythe. pivot pin '12 for operating the thumb and fingers, as above described. I V

-What I claim is. v 1 r.

1. In an artificial hand, comprising a han dy and t umb ee finge 'ef lated thereto, a brachial sleeve, forearm supporting elements on said sleeve, lower arm supporting elements jointed to said forearm supporting elements, an inverted dish-shaped wrist member at the outer ends of said lower arm supporting elements, a cup-shaped member adapted to be secured to the arm stump, a screw bolt extending from said stump cup, a square portion to said bolt and means for rotatingly displacing said bolt relatively to said stump cup and for looking it thereto in the desired relative position, said bolt passing through, and being freely guided in, the bottom of said wrist member, means operable by said square bolt portion for simultaneously actuating the thumb and fingers, comprising a forked lever on said bolt, a tri-armed lever secured to the root of the thumb, the one arm of said lever cooperating with said forked lever and actuating the thumb, the second arm actuat ing the two rigidly connected first fingers and the third arm actuating the remaining two fingers, and means for locking thumb and fingers in the respective cooperative position for allowing rotation of the hand, or of the stump, relative to the wrist without at the same time also actuating, or interfering with, the thumb and finger mechanisms.

2. In an artificial hand, comprising ahand body and thumb and fingers articulated thereto, the combination of a stump member to be fixed to the underarm stump, a wrist member to be fixed to the upperarm, means extending from said stump member with controlled capability of relative rotation, passing freely through said wrist member and adapted to simultaneously actuate the thumb and the fingers on rotation of said stump member, and means for locking thumb and fingers in the respective cooperating position and for rotating the hand, or the stump, relative to said wrist member without at the same time also actuating, or interfering with, the thumb and finger mechanisms, comprising a hand operable ratchet mechanism operatively interposed between said wrist member and said hand body, a lock lever controllable by said ratchet mechanism and, if required, also by hand, for normally locking said wrist member and said hand body, and said ratchet mechanism in the operative position adapted to positively control said thumb and finger mechanisms.

In witness whereof I have hereunto set my name.

KARL FELIX ROHRMANN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

